Multi-process detachable heat exchanger and dedicated heat exchange plate thereof

ABSTRACT

The disclosure relates to a multi-pass removable plate heat exchanger without a need of arranging interfaces or connections on a mobile pressure plate, and a specific heat transfer plate therefor. The heat transfer plate has a plurality of lateral regions, where a plurality of mutually communicative lateral-pass partitions or mutually isolated pass partitions are formed with specially shaped gaskets. With such kind of heat transfer plates, a multi-pass removable plate heat exchanger without a need of arranging interfaces or nozzles on the mobile pressure plate may be constructed. The disclosure further relates to a specially shaped gasket to allow construction of a multi-pass removable plate heat exchanger without a need of arranging interfaces or nozzles on the mobile pressure plate. The multi-pass removable plate heat exchanger comprises a fixed pressure plate, a mobile pressure plate, and a plate pack where a plurality of the heat transfer plates configured with corresponding gaskets are assembled to form alternating cold and hot fluid flow channels.

FIELD OF THE INVENTION

The present disclosure relates to a removable plate heat exchanger, andmore specifically relates to a multi-pass removable plate heat exchangerwithout a need of installing connections to a mobile pressure plateside, and a dedicated heat transfer plate therefor.

BACKGROUND

A plate and frame heat exchanger is generally referred to as a plateheat exchanger (PHE), which was originated from the European foodindustry over 60 years ago, when there was a demand for a heat exchangerthat was efficient, energy-saving, structurally compact, easy to clean,and adaptable to change of design conditions. PHEs could satisfy suchinitial requirements. Currently, those basic requirements are stillpresent, and the PHEs have been widely used in various industrial fieldsthroughout the world, e.g., refrigerating, heating and ventilation,air-conditioning, and oil cooling. Due to its characteristics such ashigh heat transfer efficiency, low heat loss, light-weighted and compactstructure, less space demand, ease of assembly and cleaning, wide rangeof operating parameters, and long service life, etc., the plate heatexchanger is an ideal device for liquid-to-liquid and liquid-to-gas heatexchange. Under a same pressure loss, the plate heat exchanger has aheat transfer coefficient 3 to 5 times higher than that of a tubularheat exchanger, but with only a fraction of space requirement; besides,the heat recovery rate of the plate heat exchanger may amount to 90%above. Common plate heat exchangers available in the market are formedby stacking a series of metal sheets with certain corrugated patterns.

Variations of plate heat exchangers mainly include removable (frame)types and brazed/welded types. Profiles of heat transfer plate mainlyinclude herringbone corrugated patterns, horizontally corrugatedpatterns, and dimpled patterns. The removable plate heat exchanger isthe most commonly used compact heat exchanger type for heating, coolingor heat recovery in various industrial fields. The popularity of thistype of exchanger is attributed to its various unique and advantageousproperties, including a high heat transfer efficiency, a modularstructure, ease of assembly and disassembly, convenience for cleaningand maintenance, and a high degree of flexibility in its sizing andconfiguration to match a particular application duty. A plate pack of atypical removable plate heat exchanger comprises a series ofsequentially assembled metal sheets, where an elastic sealing gasket isinstalled between every two metal sheets to thereby form a hot fluidflow channel and a cold fluid flow channel that are mutually alternatingand isolated. Sealing gaskets are mounted to seal corner ports and theperiphery of heat transfer plates to prevent mixing of the cold and hotfluids as well as leakage of any fluid through the periphery to theambient. The plate pack is tightly compressed by a frame system toprovide pressure bearing and sealing capabilities. The frame systemcomprises mainly: a front fixed pressure plate, a rear mobile pressureplate, a top carrying beam, and clamp bolts distributed around. Duringthe assembly process, the clamp bolts are tightened to an appropriatepressure degree to secure all flow channels free from leakage, withoutcrushing the heat transfer plates. Connections of different types andshapes are provided on the fixed pressure plate and/or the mobilepressure plate to allow the cold and hot fluid mediums to enter and exitthe heat exchanger.

As shown in FIG. 1A, a conventional removable plate heat exchangergenerally comprises: 1) a plate pack including a leading plate 5′, anend plate 4′, and a plurality of regular heat transfer plates 3′; 2) aframe system which comprise a fixed pressure plate 1′, a mobile pressureplate 2′, a top guide bar 6′, a bottom guide bar 7′, a back post 8′, anda clamp bolt 9′; 3) ancillary components which comprise a lock washer10′, a fastening nut 11′, a support foot 13′, a roller assembly 14′, anda protection board 15′, etc.; and 4) four connections 16′ attached tothe fixed pressure plate to allow the cold and hot fluid media to enterand exit the heat exchanger. Further, as shown in FIG. 1B, the leadingplate 5′, the end plate 4′ and the regular heat transfer plate 3′ allcomprise two components: a metal sheet and a sealing gasket, wherein themetal sheet is a thin metal sheet impressed with a corrugated surface, asealing groove, and ports. The corrugated profile is the most importantfeature of the heat transfer plate, as the profile not only helps tointensify the heat transfer by enhancing turbulence, but also improvesthe rigidity of the thin sheet, thereby enhancing the pressure bearingcapacity of the plate heat exchanger. The enhanced turbulence also helpsto reduce formation of sediments or fouling, which creates a“self-cleaning” effect; the sealing gasket is installed in the sealinggroove along the periphery of the metal sheet so as to seal theperiphery between the metal sheets, thereby preventing the fluids fromleaking to the external; all or some of the corner ports are sealedaccording to flow configurations such that the cold and hot fluids flowalong their alternate channels. Additionally, the sealing gasket in portareas can be designed into a two-channel sealing structure with adraining hole leading to the ambient. The media may flow out from thedraining hole in case of a leakage from the first line of sealing, thusreducing the chance of mixing of the cold and hot media. The draininghole can also serve as an early leakage warning and detection mechanism.Additionally, different glue types may be applied to the sealing gasketdepending on different working media and operating temperatures.

As an important component of the plate heat exchanger, the plate packsignificantly influences the overall performance and working conditionof the plate heat exchanger. Therefore, the heat transfer and thecirculation characteristic of the removable plate heat exchanger may beadjusted and optimized by changing the following parameters: 1)geometric profiles of the heat transfer plate; 2) dimension (width andlength) of the heat transfer plate; 3) dimension of the corner ports; 4)number of plates; and 5) respective numbers of flow passes for the coldand hot flow channels. It needs to be particularly noted that the flowpass and the flow channel in the art are two technical terms associatedwith each other but having different meanings. The flow pass refers to agroup of parallel channels where any given medium flows in the samedirection, while the flow channel refers to a medium flow channel formedby two adjacent sheets inside the plate heat exchanger. Generally, aplurality of flow channels are connected in parallel or in series toform different combinations of cold and hot medium channels. Based onthe definitions above, it is seen that FIG. 1A shows a single passdesign of the removable plate heat exchanger, and FIG. 1B represents, byarrows, the flow directions of respective cold and hot fluids, whereinin the single pass design, the cold and hot fluids flow in oppositedirections, thereby generating more favorable temperature profiles forheat transfer. Because the connections for a “U”-shaped single pass areall attached to the fixed pressure plate and meanwhile the inlet andoutlet piping for a same fluid are configured in parallel, engineeringinstallation is simplified, which facilitates easy disassembly andassembly. It needs to be particularly noted that the rear end plate 4′and the leading plate 5′ are not only different from the heat transferplate 3′ in terms of quantity, but also different from the heat transferplate 3′ in terms of the shape of sealing gasket. For example, due tothe structural requirement, the sealing gasket s of the leading plate 5′as shown in FIG. 1B need to seal all of the four corner ports, while thesealing gasket of a common heat transfer plate 3′ only seals some of thecorner ports; in addition, the four corner ports of the rear end plate4′ do not penetrate through the metal thin sheet, while the corner portsof the common heat transfer plate 3′ have to penetrate through the metalthin sheet. To simplify illustration and to highlight the technicalcontributions of the present disclosure, the rear end plate, the leadingplate, and the heat transfer plate will not be specificallydistinguished unless confusion is otherwise caused, but are generallyreferred to as a heat transfer plate.

To satisfy a heat transfer duty that requires an extremely high heatrecovery efficiency at a very small temperature difference, a heattransfer plate with a relatively high aspect ratio is needed. However, amaximum length of the heat transfer plate is limited to a feasibleaspect ratio, because if the heat transfer plate has too high an aspectratio, the heat exchanger becomes unstable in structure and spatiallyless optimized for installation; therefore, the height of the heattransfer plate is more frequently limited by the available height forinstalling the device. This limitation may be alleviated by designing amulti-pass heat exchanger, such that the cold and hot fluids are turnedinto opposite directions by a stopper plate in each flow channel.Theoretically, varying the number of flow passes may satisfy the need ofany efficient heat transfer duty; multi-pass design is requiredparticularly for industrial applications with a low flow rate or a closeapproach temperature. FIG. 2 shows a schematic structure and the workingprinciple of a conventional three-pass removable plate heat exchanger.The heat exchanger comprises a plate pack 3, a fixed pressure plate 1,and a mobile pressure plate 2. The cold fluid enters the heat exchangerfrom a cold fluid inlet connection 4 attached to the fixed pressureplate 1, flows upwards in the first flow pass, flows downwards in thesecond flow pass, and flows upwards again in the third flow pass, andfinally flows out of the heat exchanger from a cold fluid outletconnection 7 on the mobile pressure plate 2. Likewise, the hot fluidflows in from a hot fluid inlet connection 9 attached to the mobilepressure plate 2, flows reversely through the three passes, and thenflows out of the heat exchanger via a hot fluid outlet connection 5attached to the fixed pressure plate 1.

In a conventional multi-pass heat exchanger, the plate pack is dividedinto a plurality of sections between the fixed pressure plate and themobile pressure plate. A stopper plate 6 is mounted between two adjacentsections to force a fluid to change its flow direction between passes.The stopper plate 6 differs from a regular heat transfer plate 3 in thattwo corner ports of the stopper plate 6 are blocked. Despite of the manyadvantages, conventional multi-pass designs have a number of problemsand inconveniences in practical applications. As shown in FIG. 2, aconventional multi-pass design always needs to install a cold fluidoutlet connection 7 and a hot fluid inlet connection 9 on the mobilepressure plate 2. In other words, the inlet and outlet connections forthe cold and hot fluid, respectively, have to be attached to theopposite ends of a multi-pass heat exchanger. Therefore, for maintenanceand cleaning, it is needed to loosen the mobile pressure plate 2 to openthe plate pack in order to gain access to each heat transfer plate.However, because one end of the mobile pressure plate 2 is physicallyattached to the connections for the cool/hot fluids, it is required tofirst disconnect the fluid piping 8 and 10 connected to the mobilepressure plate 2. This makes the installation and maintenancecumbersome, time-consuming, and costly. This is why a multi-passconfiguration design scheme is often excluded from actual applications,despite of the obvious advantages in thermal performance.

Further, as shown in FIG. 2, due to the working principle of theconventional multi-pass design, the flow directions of the cold and hotfluid flow channels at the opposite sides of each stopper plate 6 are inco-current flows (local co-currency) 11. Such local co-current flows 11deteriorate to a certain extent the overall heat transfer efficiency ofthe heat exchanger. In additional, the conventional multi-pass designneeds a series of flow reversal, compression, expansion, andre-distribution in the port area of each stopper plate, which causes anadditional flow pressure drop. Although there are increasing demands onefficient heat exchangers in industrial applications geared towardsenvironment protection, energy saving, and energy recovery, their widerapplications are hindered by the above drawbacks of the conventionalmulti-pass plate heat exchangers, particularly by the inconveniences inthe installation and maintenance process due to the existence of pipingand connections on the mobile pressure plate.

SUMMARY OF THE PRESENT INVENTION

To solve various problems existing in the prior art, and particularly toovercome the technical limitations in the prior art that connectionsneed to be arranged at two opposite ends of a heat exchanger with amulti-pass design, the present disclosure provides a novel structure anddesign of a multi-pass heat transfer plate, which allows for moreefficient and easier maintenance process, by allowing multi-passremovable plate heat exchanger without the need of arranging connectionson a mobile pressure plate.

To address some performance drawbacks and operational inconvenience inuse of a conventional multi-pass plate heat exchanger described above,the present disclosure further provides a novel heat transfer plateconstruction, which has an equivalent or better heat transferperformance compared with a traditional multi-pass plate, but withoutkey drawbacks of the traditional multi-pass plate heat exchanger.

Specifically, the present disclosure provides a heat transfer plate fora multi-pass removable plate heat exchanger. The heat transfer plate hasa plurality of lateral partitions, where a plurality of mutuallycommunicative lateral-pass partitions or mutually isolated longitudinalpass partitions may be formed by specially shaped gaskets. With thisnovel type of heat transfer plates, a multi-pass removable plate heatexchanger without a need of arranging connections at the mobile pressureplate may be constructed. The present disclosure further provides aspecially shaped and constructed gasket to implement a multi-passremovable plate heat exchanger without a need of arranging connectionsat the mobile pressure plate.

According to one of the technical solutions of the present disclosure, amulti-pass removable plate heat exchanger can be implemented, whichcomprises: a fixed pressure plate, a mobile pressure plate, and a platepack sandwiched between the fixed pressure plate and the mobile pressureplate via clamp bolts. The plate pack further comprises a plurality oflateral-pass plates configured with specially shaped sealing gaskets toform two or more successively communicating lateral partitions. Thelateral-pass plates are assembled to form the plate pack with mutuallyalternating cold and heat fluid flow channels, the number of passes onthe multi-pass removable plate heat exchanger being equal to the numberof lateral partitions on each lateral-pass plate.

Preferably, in the multi-pass removable plate heat exchanger accordingto the technical solution above, connections are only arranged on thefixed pressure plate, without a need of arranging connections on themobile pressure plate.

Preferably, in the multi-pass removable plate heat exchanger accordingto the technical solution above, the lateral-pass plate may typicallyhave two, three, or four lateral partitions.

According to another technical solution of the present disclosure, amulti-pass removable plate heat exchanger can be implemented, whichcomprises: a fixed pressure plate, a mobile pressure plate, and a platepack sandwiched between the fixed pressure plate and the mobile pressureplate via clamp bolts. The plate pack further comprises one section oftwo-zone lateral-pass plates, and (N−1) sections of two-zonelateral-partition plates. Each two-zone lateral-pass plate is configuredwith specially shaped sealing gaskets to form two mutually communicatinglateral partitions. Each two-zone lateral-partition plate is configuredwith specially shaped sealing gasket to form two mutually isolatedlateral partitions. The section of two-zone lateral-pass plates isallocated immediately adjacent to the mobile pressure plate to forceboth hot fluid and cold fluids to make a U-turn, while (N−1) sections oftwo-zone lateral-partition plates are arranged adjacent to the fixedpressure plate. The thus assembled plate pack creates mutuallyalternating cold and heat fluid flow channels, where each fluid entersthe heat exchanger via the fixed pressure plate, flows towards themobile pressure plate along one side of the partition, makes a U-turnupon reaching the mobile pressure plate, and then flows back along theother side of the partition, and lastly exits the heat exchanger via thefixed pressure plate. The total number of passes achieved in this noveltype of the multi-pass removable plate heat exchanger is equal to 2N,where N is a natural number greater than or equal to 2.

Preferably, in the multi-pass removable plate heat exchanger accordingto the technical solution above, connections are only arranged on thefixed pressure plate, without a need of arranging connections on themobile pressure plate.

Preferably, in the multi-pass removable plate heat exchanger accordingto the technical solution above, the sections with lateral-pass platesare allocated immediately adjacent to the mobile pressure plate, andwhile the remaining sections of lateral-partition plates are allocatedadjacent to fixed pressure plate to achieve the remaining flow passes.

According to a further technical solution of the present disclosure, alateral-pass plate specific for the novel type of multi-pass removableplate heat exchanger is provided, wherein the heat transfer plate is alateral-pass plate, wherein flat groove patterns are provided at theperiphery and in the interior of the lateral-pass plate for configuringsealing gaskets to thereby form two or more successively communicativelateral partitions.

According to a further technical solution of the present disclosure, alateral-partition plate specific for the novel type of multi-passremovable plate heat exchanger is provided, wherein the heat transferplate is a lateral-partition plate, wherein flat groove patterns areprovided at the periphery and in the interior of the lateral-partitionplate for configuring sealing gaskets to thereby form two or moremutually isolated lateral partitions

Preferably, in the heat transfer plate specific for the novel type ofmulti-pass removable plate heat exchanger according to the technicalsolution above, the heat transfer plate may possess differentthermal-hydraulic performance characteristics through variations ingeometrical profiles, wherein heat transfer plates with differentgeometrical profiles may also be arranged in a hybrid fashion within thesame plate pack to form a mixed plate pack.

Preferably, in the heat transfer plate specific for the novel type ofmulti-pass removable plate heat exchanger according to the technicalsolution above, the geometrical profile variations may include, but notlimited to chevron corrugation angles, circular or irregular dimples,studs, or other structures with the effect of enhancing heat transferefficiency.

Preferably, in the heat transfer plates specific for the novel type ofmulti-pass removable plate heat exchanger according to the technicalsolution above, sealing and/or partitioning functionalities of thesealing gaskets may be partially or completely replaced by other sealstructures or mechanisms.

Preferably, in the heat transfer plate specific for the novel type ofmulti-pass removable plate heat exchanger according to the technicalsolution above, the other seal structures or mechanisms may include, butnot limited to brazing, welding, diffusion bounding or mechanicalcontact sealing.

According to a further technical solution of the present disclosure, asealing gasket specific for the lateral-pass plate is provided, whereinthe sealing gasket is situated inside flat grooves provided at theperiphery and in the interior of the lateral-pass plate, such that thelateral-pass plate is formed with two or more lateral partitions thatare successively in communication.

According to a further technical solution of the present disclosure, asealing gasket specific for the lateral-partition plate is provided,wherein the sealing gasket is situated within flat grooves provided atthe periphery and in the interior of the lateral-partition plate, suchthat the lateral-partition plate is formed with two or more lateralpartitions that are mutually isolated.

Compared with conventional single-pass designs and conventionalmulti-pass designs, the multi-pass removable plate heat exchanger (PHE)constructed according to the present disclosure has the followingadvantages:

Improved maintainability: because no connections are arranged at themobile pressure plate side, the multi-pass heat exchanger according tothe present disclosure may be easily disassembled for cleaning andrepair like a conventional single-pass heat exchanger;

Increased effective heat transfer area: because i) with fewer cornerports in lateral-pass plate, the percentage of non-heat transfer area isreduced; ii) with decreased peripheral length of the heat transferplates, heat loss through the external area in direct contact with theambient is reduced; iii) internal gasket grooves can be made verynarrow, which reduces loss in effective heat exchange areas;

Improved overall heat transfer efficiency: With lateral-pass plates,multiple pass heat exchanger can be formed without occurrence of localco-currency between each neighboring pass as present in conventionalmulti-pass designs, and the overall heat transfer efficiency of the heatexchanger is improved;

Reduced flow pressure drop: because the turn of flow direction on alateral-pass plate is relatively gentle and the fluid velocities aresubstantially constant during each lateral turn, there is no apparentcompression and expansion in distribution areas, and the additionalpressure drop due to directional turn associated with multiple passes issmaller;

Reduced heat loss from the ambiance: because the interface area with theambient for the same heat transfer area is reduced, the heat loss of theentire heat exchanger is reduced;

More compact structure: due to the small aspect ratio of each heattransfer plate, the overall shape of the heat exchanger tends to becubic, such that the space requirement for the same amount of total heattransfer area can be substantially reduced;

Overall more efficient heat exchanger: due to various advantages above,a multi-pass heat exchanger that is thermally more efficient andeasier-to-maintain may be constructed according to the presentdisclosure, thereby satisfying the demand of more efficient and moreeasy-to-service heat exchangers in a wide range of applications such asenergy recovery, process isolation, and pressure breaker, etc.

The features, working principles, and other advantages of the presentdisclosure will become apparent through further illustration inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Hereinafter, the present disclosure will be described through exampleswith reference to the accompanying drawings, wherein:

FIG. 1A is a structural exploded view of a single-pass removable plateheat exchanger according to the prior art;

FIG. 1B is a structural schematic diagram of various kinds of heattransfer plates formed by metal sheets and sealing gasket s in FIG. 1A;

FIG. 2 is a schematic diagram of the working principle of a conventionalthree-pass removable plate heat exchanger that requires connections onthe mobile pressure plate;

FIG. 3A is a schematic diagram of the working principle of alateral-pass plate having two lateral partitions using a hot side flowchannel as an example according to an embodiment of the presentdisclosure;

FIG. 3B is a schematic diagram of the working principle of alateral-pass plate having two lateral partitions using a cold side flowchannel as an example according to an embodiment of the presentdisclosure;

FIG. 4 is a simplified structural exploded view of a two-pass removableplate heat exchanger without a need of arranging connections on mobilepressure plate according to an embodiment of the present disclosure;

FIG. 5A is a schematic diagram of the working principle of alateral-pass plate having three lateral partitions using a hot side flowchannel as an example according to an embodiment of the presentdisclosure;

FIG. 5B is a schematic diagram of the working principle of alateral-pass plate having three lateral partitions using a cold sideflow channel as an example according to an embodiment of the presentdisclosure;

FIG. 6A is a schematic diagram of the working principle of alateral-partition plate having two lateral partitions using a hot sideflow channel as an example according to an alternative embodiment of thepresent disclosure;

FIG. 6B is a schematic diagram of the working principle of alateral-partition plate having two lateral partitions using a cold sideflow channel as an example according to an alternative embodiment of thepresent disclosure; and

FIG. 7 is an exploded view of a simplified structure of a six-passremovable plate heat exchanger without a need of arranging connectionsat a mobile pressure plate side according to an alternative embodimentof the present disclosure.

DETAILED DESCRIPTION

Hereinafter, the technical contents, structural features, and achievedtechnical objects and effects of the preferred embodiments of thepresent disclosure will be illustrated in detail with reference to theaccompanying drawings.

The present disclosure overcomes the following technical bias regardinga multi-pass plate heat exchanger: the multi-pass plate heat exchangerneeds to arrange inlet and outlet interfaces for cold and hot fluids, aswell as the connections therefor, at two opposite sides of the fixedpressure plate and mobile pressure plate of a heat exchanger. Thistechnical bias is extensively seen in prior technical literaturesdescribing multi-pass heat exchangers, but the Inventor of the presentdisclosure fundamentally overthrows this technical bias throughinnovative technical solutions. A heat transfer plate for a multi-passremovable plate heat exchanger according to the present disclosure has aplurality of lateral partitions, which, in combination with speciallyshaped gaskets, may form a plurality of communicative flow channels ormutually isolated flow channels. In contrast with the dedicated heattransfer plate of the present disclosure, the heat transfer plate in theprior art does not have a plurality of mutually communicative orisolated lateral partitions, which is an integral zone for circulatingcold and hot fluids.

According to a preferred embodiment of the present disclosure, a keycomponent for solving the technical problem of a conventional multi-passplate heat exchanger is a heat transfer plate having a plurality oflateral partitions. These lateral partitions are further fitted withspecially shaped sealing gaskets, such that a plurality of mutuallycommunicative lateral-pass flow channels may be implemented between twoadjacent plates, and such a special heat transfer plate may be referredto as a lateral-pass plate. Further, with the lateral-pass plate of thepresent disclosure, a multi-pass plate heat exchanger without a need ofarranging connections on the mobile pressure plate may be built, thenumber of its passes corresponding to the number of lateral partitionson each lateral-pass plate. The working principle of the lateral-passplate of the present disclosure is described below.

FIG. 3A shows a lateral-pass plate having two lateral partitions using ahot side flow channel as an example; FIG. 3B shows a lateral-pass platewith two lateral partitions using a cold side flow channel as anexample. Different from FIG. 1B where four corner ports of aconventional heat transfer plate are fixedly disposed at the upper andlower two ends of the plate, the positions of the four corner ports ofthe lateral-pass plate 12 of the present disclosure varying withdifferent numbers of passes. As shown in FIG. 3A, a hot fluid 15 flowsinto a right-side partition of the heat transfer plate 12 from a hotside inlet corner port 14 at the upper right corner. Elastic sealinggaskets 16 are mounted in a gasket groove at a periphery of a metalsheet of the lateral-pass plate 12 to seal the periphery between metalsheets for preventing leakage of the fluid to the external, and to sealrelevant corner ports according to flow configurations such that thecold and hot fluids flow along respective flow channels, therebypreventing the hot fluid 15 from contacting with the cold side fluidflowing through an adjacent cold side corner port 13. The sealinggaskets 16 and inner partition gaskets 17 guide the hot fluid 15 to flowtowards a bottom portion of the sheet. Inner partition gaskets 17 and anopening 18 between peripheral gaskets let the hot fluid 15 to laterallyflow towards the left partition of the heat transfer plate. Next, thehot fluid 15 further flows upwards from here and finally flows out ofthe hot side outlet corner port 19; likewise, the elastic sealing gasket16 may prevent the hot fluid 15 from contacting with the cold side fluidflowing through a neighboring cold side corner port. It needs to benoted that compared with the stopper plate 6 shown in FIG. 2 as theprior art, the opening 18 that changes the pass direction has arelatively gentle turn of flow direction; and the fluid velocity issubstantially constant during direction turn, wherein there is noapparent compression and expansion of fluids through the distributionarea; therefore, the increase in pressure drop due to direction turn ofmultiple passes is relatively small.

The pass for the cold side fluid as shown in FIG. 3B is just opposite tothe pass for the hot side fluid as shown in FIG. 3A. As shown in FIG.3B, the cold fluid 20 flows into the left side partition of the heattransfer plate from the cold side inlet corner port 21 at the upper leftcorner. Likewise, the elastic sealing gaskets 16 are configured forpreventing the cold fluid 20 from contacting with the hot side fluidflowing through a neighboring hot side corner port. The sealing gaskets16 and inner partition gaskets 17 guide the cold fluid 20 to flowtowards a bottom portion of the sheet. The inner partition gaskets 17and the opening 18 between peripheral gaskets let the cold fluid 15 tolaterally flow towards a right-side partition of the sheet. Next, thecold fluid 20 flows upwards from here and finally flows out of the coldside outlet corner port 22. According to the present disclosure, becausethe circulating areas of the cold and hot fluids are identical but havecompletely opposite flow directions, a complete counter-current flowconfiguration is achieved, which in turn leads to a maximal heattransfer potential.

FIG. 4 shows an exploded view of a simplified structure of a two-passheat exchanger using the lateral-pass plate having two lateralpartitions as shown in FIG. 3. As shown in FIG. 4, the heat exchangercomprises a fixed pressure plate 1, a mobile pressure plate 2, and aplate pack sandwiched between the fixed pressure plate 1 and the mobilepressure plate 2 via clamp bolts, the plate pack being further assembledby a series of lateral-pass plates 12 having two lateral partitions.Additionally, those skilled in the art may understand that the heattransfer plates as the rear end plate and the leading plate may beregarded as specially shaped lateral-pass plates 12, and their sealinggaskets and corner port structures may be configured correspondingly asshown in FIG. 1 according to needs. As shown in FIG. 4, eachlateral-pass plate 12 itself is used for implementing a lateral U-turnof the flow direction, thereby allowing the hot side and cold side fluidinlet and outlet connections 4, 5, 7, and 9 to be solely arranged at thefixed pressure plate 1 side, such that it is unnecessary to arrange anyconnections at the mobile pressure plate 2 side; in this way, themulti-pass removable plate heat exchanger according to the presentdisclosure is as convenient as the conventional single-pass heatexchanger in terms of mounting, piping, assembling, disassembling andmaintenance.

The lateral-pass plate having two lateral partitions according to thepresent disclosure may be easily extended to other multi-passarrangements, e.g., theoretically, the number of lateral partitions ofeach lateral-pass plate may be increased to 3 or 4 or higher dependenton operating duties. In actual industrial applications, a lateral-passplate having two to four lateral partitions is possibly the mostpractical and most economical. FIG. 5A shows a structure and the workingprinciple of a lateral-pass plate having three lateral partitions usinga hot flow channel as an example according to an embodiment of thepresent disclosure; FIG. 5B shows a structure and the working principleof a lateral-pass plate having three lateral partitions using a coldflow channel as an example according to an embodiment of the presentdisclosure. To those skilled in the art, the structure and the workingprinciple of the lateral-pass plate with three lateral partitions may beeasily understood based on the above detailed depiction of thelateral-pass plate with two lateral partitions with reference to FIG. 5Aand FIG. 5B, which are thus not detailed herein. Further, those skilledin the art can easily understand that a three-pass heat exchanger usinga lateral-pass plate with 3 lateral partitions as shown in FIG. 5likewise allows the hot side and cold side fluid inlet and outletconnections to be all arranged at the fixed pressure plate side, suchthat it is unnecessary to arrange any connections to the mobile pressureplate side.

As mentioned above, because the number of passes of the multi-pass heatexchanger that only uses lateral-pass plates corresponds to exactly thenumber of lateral partitions on each lateral-pass plate, it may beunderstood that the number of passes of the plate heat exchangermanufactured according to the above embodiments of the presentdisclosure increases in a lateral direction. Although the number ofpasses may arbitrarily increase to any number in the lateral directiontheoretically, the lateral-pass plate with 2, 3, or 4 lateral-passpartitions is likely most practical and economical due to unfavorabledimension increase in horizontal direction at higher pass numbers; inother words, the number of passes of the plate heat exchanger employinglateral-pass plates is preferably 2 to 4. In view of the above, theInventor of the present disclosure further provides an alternativeembodiment based on a combined implementation of lateral-pass plates andlateral-partition plates, such that the number of passes of themulti-pass plate heat exchanger manufactured by the present disclosuremay increase without limitation. Hereinafter, this alternativeembodiment of the present disclosure will be specifically described.

FIG. 6A and FIG. 6B show a construction structure and a workingprinciple of the heat transfer plate in this alternative embodiment,wherein FIG. 6A shows a heat transfer plate having two lateralpartitions using a hot flow channel as an example according to analternative embodiment of the present disclosure; FIG. 6B shows a heattransfer plate having two lateral partitions using a cold flow channelas an example according to an embodiment of the present disclosure. Asshown in the figures, this alternative embodiment uses a same heattransfer plate, but arrangements of corner ports and the shapes ofsealing gaskets are slightly different; particularly, the internalpartition gasket 17 extends through the entire length of the pass, suchthat the lateral flow of the fluid is completely blocked. Thisalternation is referred to in the present disclosure as alateral-partition plate, which has two mutually isolated longitudinalpass partitions. From this point of view, it is prominently differentfrom the lateral-pass plate, which has two or more mutuallycommunicative lateral partitions. Additionally, the cold and hot flowchannels in each longitudinal pass partition of the lateral-partitionplate as shown in FIG. 6A and FIG. 6B are identical to the twoconventional heat transfer plates 3′ shown in FIG. 1B, which are thusnot detailed here.

By using the two-zone lateral-pass plate shown in FIG. 3 and thelateral-partition plate shown in FIG. 6 in combination, a higher numberof passes meeting demanding thermal duty requirements can beimplemented, e.g., 4, 6, 8, 10 or any even number of passes. It needs tobe noted that because each heat transfer plate has two partition passes,the number of passes achievable for the entire heat exchanger can beviewed as any number, without being limited to even number only, if eachheat transfer plate is used as the reference. In a heat exchanger withsuch a high number of passes, the lateral-pass plates shown in FIG. 3are to be situated adjacent to the mobile pressure plate side, while theremaining passes using the lateral-partition plates shown in FIG. 6 areto be situated adjacent to the fixed pressure plate. Actually, thelateral-pass plate in this multi-pass construction allows the cold andhot fluids to make a 180° U-turn upon reaching the mobile pressure plateso as to avoid the need of having any connections on the mobile pressureplate.

FIG. 7 shows a structure and the working principle of a six-passremovable plate heat exchanger according to an alternative embodiment ofthe present disclosure. As illustrated in FIG. 7, the heat exchangercomprises a fixed pressure plate 1, a mobile pressure plate 2, and aplate pack 3 sandwiched between the fixed pressure plate 1 and themobile pressure plate 2 via clamp bolts, wherein the plate pack 3further comprises one section of two-zone lateral-pass plates for thetwo passes (third and fourth passes) directly adjacent to the mobilepressure plate, and two sections of lateral-partition plates for theremaining other passes (first and sixth passes, and second and fifthpasses). Hot side and cold side fluid inlet and outlet connections 4, 5,7, and 9 are all arranged on the fixed pressure plate 1, such that it isunnecessary to arrange any connections on the mobile pressure plate 2.Hereinafter, the working principle of the six-pass removable plate heatexchanger is illustrated using a hot side flow channel as an example,where the hot fluid enters the heat exchanger from the hot fluid inletconnection 9 on the fixed pressure plate 1, and the first pass and thesecond pass are implemented via lateral-partition plates, where thefirst pass flows upwardly and the second pass flows downwardly; next,the third pass and the fourth pass are implemented via the two-zonelateral-pass plate, where the third pass flows upwardly, and the fourthpass flows downwardly; finally, the fifth pass and the sixth pass areimplemented via the lateral-partition plates shared with the second passand the first pass, respectively, wherein the fifth pass flows upwardlyand the sixth pass flows downwardly; and finally, the hot fluid flowsout of the heat exchanger from a hot fluid outlet connection 5 on thefixed pressure plate 1. The cold side fluid flow channel is reverse tothe hot side fluid flow channel.

As shown in FIG. 7, the lateral-pass plates are only used in the thirdand fourth passes immediately adjacent to mobile pressure plate side,while the lateral-partition plates are used in other passes; in thisalternative multi-pass design, the lateral-pass plate is forfacilitating a longitude U-turn of the flow direction, to allow the hotside and cold side fluid inlet and outlet connections 4, 5, 7, and 9 tobe all arranged on the fixed pressure plate 1, such that it isunnecessary to arrange any connections on the mobile pressure plate 2;in this way, the multi-pass removable plate heat exchanger according tothis alternative multi-pass construction is as convenient as theconventional single-pass heat exchanger in terms of mounting, piping,assembling, disassembling and maintenance.

Based on operating parameters and the required number of passes, theheat transfer plate described by the present disclosure has thefollowing two typical application examples. The heat transfer platerequired by the two application examples may be provided by a same platepressing die, except for the number of corner ports needed to be cut,and the shapes and configurations of sealing gaskets.

First Application Example

In the first application example, there are only lateral passes withoutlongitudinal passes. In other words, only lateral-pass heat transferplates are used, while partition heat transfer plate is not used.Although the number of lateral passes is not limited theoreticallyaccording to the principle of the present disclosure, the presentapplication example is more suitable for implementing a multi-passremovable plate heat exchanger with 2, 3, or 4 passes in actualapplications due to consideration of unfavorable dimension increase inhorizontal direction.

-   -   a heat transfer plate with 2, 3 or 4 lateral partitions is        molded using a same pressing die;    -   appropriately shaped sealing gaskets are mounted to each heat        transfer plate to form the desired number of lateral partitions;    -   a plurality of lateral-pass plates configured with corresponding        sealing gaskets are assembled together to form a plate pack with        alternating cold and hot fluid flow channels;    -   an integral multi-pass removable plate heat exchanger is        implemented by sandwiching the plate pack between the front        fixed and rear mobile pressure plates via clamp bolts;    -   only four connections need to be attached to the fixed pressure        plate irrespective of the number of passes of the heat        exchanger.

Second Application Example

In the second application example, not only the lateral passes but alsothe longitudinal passes are employed; in other words, lateral-pass heattransfer plates and partition heat transfer plates are used incombination. A second application example of the present disclosure issuitable for circumstances requiring a higher number of passes,including 4, 6, 8, 10, . . . 2N (any even number) passes (the number ofpasses achievable for the entire heat exchanger can be viewed as anynumber, without being limited to even number only, if each heat transferplate is used as the reference.). In this application example, there isno structural limitation on the maximum number of passes.

-   -   a heat transfer plate with 2 lateral partitions is molded using        a same pressing die;    -   Appropriately shaped sealing gaskets are mounted to each heat        transfer plate to form the lateral-partition plate described        above. The heat transfer plate of this type is used in all        passes other than the two passes immediately adjacent to mobile        pressure plate.    -   appropriately shaped sealing gaskets are mounted to each        lateral-pass heat transfer plate to form the lateral-pass plate        described above. This type of heat transfer plate is suitable        for the two passes immediately adjacent to mobile pressure        plate.    -   a plurality of heat transfer plates configured with        corresponding sealing gaskets are assembled to form a plate pack        with alternating cold and hot fluid flow channels, wherein the        lateral-pass plates are used in the two passes immediately        adjacent to mobile pressure plate.    -   an integral multi-pass removable plate heat exchanger is        implemented by sandwiching the plate pack between the front        fixed and rear mobile pressure plates via clamp bolts;    -   only four connections are provided on the fixed pressure plate        irrespective of the number of passes of the heat exchanger.

In the first application example and the second application example, thelateral-pass plate for a multi-pass removable plate heat exchanger isprovided with flat grooves at the periphery and in the interior to allowsealing gaskets to form mutually communicative two or more lateralpartitions; while the lateral-partition plate for the multi-passremovable plate heat exchanger is provided with flat grooves at theperiphery and in the interior to allow the sealing gaskets to form twomutually isolated partitions.

Besides, in the actual applications, the heat transfer plate pattern orcorrugation may be customized and optimized according to actual needs ofthe heat exchange circumstances; for a scenario of large flow rates withsmall allowable pressure drops, a plate profile with a small pressureresistance should be selected; otherwise, a plate model with a largepressure resistance is selected. Additionally, when selecting suitableplates, those with too small a single-plate area should not be selected;otherwise, too many plates will be needed, and consequently theinter-plate fluid velocity would be too small, and the heat transfercoefficient would be too low; this issue should be particularlyaddressed for large heat exchangers. Specifically, the heat transferplate for the multi-pass removable plate heat exchanger may possessdifferent thermal performances through variations in geometricalprofiles, wherein the heat transfer plates with different geometricalprofiles may be combined within the same plate pack in a hybrid fashion.Variations in plate geometrical profiles may include employing differentchevron corrugation angles, circular or irregular dimple, studs, orother structures for enhancing heat transfer coefficient. Additionally,for the heat transfer plate in the multi-pass removable plate heatexchanger according to the present disclosure, sealing and partitioningfunctionalities of the sealing gaskets may be partially or completelyreplaced by other seal structures or mechanisms, which may include, butnot limited to, brazing, welding, diffusion bounding or mechanicalcontact sealing.

In the application examples of the present disclosure, illustration willbe made with a single-wall PHE as an example. In heat exchangescenarios, which require absolute prevention of mixing of two media(e.g., household water application), a double-wall PHE is mostly adoptedso as to effectively prevent leakage and mixing of fluids. To thoseskilled in the art, the pass structures and designs of the lateral-passplate and lateral-partition plate as disclosed in the present disclosuremay also be directly applied to the double-wall PHE.

What have been disclosed above are only preferred embodiments of thepresent disclosure, which, of course, cannot serve as a basis forlimiting the scope of the present disclosure. Therefore, similar,extended or equivalent embodiments using the same principles still fallwithin the scope covered by the present disclosure. It should beunderstood that the descriptions given above are intended forillustration only, not for limitation. For example, the embodiments(and/or aspects thereof) may be combined in use; an ideal number ofpasses of the lateral-pass plate might be greater than 4 in someindustrial applications. In addition, various alterations may be madebased on the teachings of the present disclosure so as to be adapted tospecific circumstances or materials without departing from the scope ofthe present disclosure. Through reading the descriptions above, manyother embodiments and alternations within the scope and spirit of theclaims are obvious to those skilled in the art.

1-20. (canceled)
 21. A multi-pass removable plate heat exchanger,comprising: a fixed pressure plate; a mobile pressure plate; and a platepack sandwiched between the fixed pressure plate and the mobile pressureplate via clamp bolts, wherein the plate pack comprises a plurality oflateral-pass plates configured with specially shaped sealing gaskets toform two or more successively communicating lateral partitions on eachlateral-pass plate, and wherein the lateral-pass plates are assembled toform the plate pack with mutually alternating cold and heat fluid flowchannels, the number of passes on the multi-pass removable plate heatexchanger being equal to the number of lateral partitions on eachlateral-pass plate.
 22. The multi-pass removable plate heat exchangeraccording to claim 21, wherein connections are only arranged on thefixed pressure plate, without a need of arranging connections on themobile pressure plate.
 23. The multi-pass removable plate heat exchangeraccording to claim 22, wherein the lateral-pass plate has typically two,three or four lateral partitions.
 24. The multi-pass removable plateheat exchanger according to claim 23, wherein a structure of the sealinggasket is configured such that fluid in the lateral partitions of twoadjacent heat transfer plates has opposite flow directions, thereforeachieving counter-current flow configuration.
 25. The multi-passremovable plate heat exchanger according to claim 24, wherein: on eachlateral-pass plate, the middle portion of sealing gasket has one or moreopenings configured as flow baffles for changing the flow directions ofthe fluid in two adjacent lateral partitions, the number of the openingsand the number of the lateral partitions satisfying the followingrelationship: S2=S1−1, where S1 denotes the number of the lateralpartitions and S2 denotes the number of the openings.
 26. The multi-passremovable plate heat exchanger according to claim 25, wherein: when thenumber of lateral partitions is even, inlet corner ports arranged on thelateral-pass plate for the fluid to pass through are disposed at a sameend of the plate as outlet corner ports thereof; and when the number ofthe lateral partitions is an odd number other than 1, the inlet cornerports for the fluid and the outlet corner ports are disposed at oppositeends of the lateral-pass plate.
 27. A multi-pass removable plate heatexchanger, comprising: a fixed pressure plate, a mobile pressure plate,and a plate pack sandwiched between the fixed pressure plate and themobile pressure plate via clamp bolts, wherein the plate pack comprisesone group of lateral-pass plates configured with specially shaped firstsealing gaskets to form on each plate two successively communicatinglateral partitions, and (N−1) groups of lateral-partition platesconfigured with specially shaped second sealing gaskets to form on eachplate two mutually isolated lateral partitions, the lateral-pass platesand the lateral-partition plates being assembled to form the plate packwith mutually alternating cold and heat fluid flow channels, the totalnumber of passes of the multi-pass removable plate heat exchanger being2N, where N is a natural number greater than or equal to
 2. 28. Themulti-pass removable plate heat exchanger according to claim 27, whereinconnections are only arranged on the fixed pressure plate, without aneed of arranging connections on the mobile pressure plate.
 29. Themulti-pass removable plate heat exchanger according to claim 27, whereinthe lateral-pass plates are applied to the two passes immediatelyadjacent to the mobile pressure plate, and the lateral-partition platesare applied to all other passes.
 30. The multi-pass removable plate heatexchanger according to claim 29, wherein a structure of the firstsealing gasket is configured such that fluid in the lateral partitionsof two adjacent heat transfer plates has counter-current flow whenflowing; a structure of the second sealing gasket is configured suchthat fluid in the two isolated lateral partitions of two adjacent heattransfer plates has counter-current flow when flowing.
 31. Themulti-pass removable plate heat exchanger according to claim 30, whereinthe first sealing gasket has one opening in interior area configured forchanging the flow directions of the fluid in the two adjacent lateralpartitions.
 32. The multi-pass removable plate heat exchanger accordingto claim 31, wherein the lateral-pass plate is 2-pass plate, andspecifically on the 2-pass lateral-pass plate, an inlet corner port forthe fluid is disposed at a same end of the plate as an outlet cornerport for the fluid.
 33. A heat transfer plate dedicated for themulti-pass removable plate heat exchanger according to claim 21, whereinthe heat transfer plate is a lateral-pass plate, flat groove patternsbeing provided at the periphery and in the interior of the lateral-passplate for configuring sealing gaskets to thereby form two or moresuccessively communicative lateral partitions.
 34. A heat transfer platededicated for the multi-pass removable plate heat exchanger according toclaim 27, wherein the heat transfer plate is a lateral-pass plate or alateral-partition plate, first flat groove patterns being provided atthe periphery and in the interior of the lateral-pass plate forconfiguring sealing gaskets to thereby form two successivelycommunicative lateral partitions; and wherein second flat groovepatterns being provided at the periphery and in the interior of thelateral-partition plate for configuring second sealing gaskets tothereby form two mutually isolated lateral partitions.
 35. The heattransfer plate dedicated for the multi-pass removable plate heatexchanger according to claim 33, wherein the heat transfer plate mayobtain different thermal-hydraulic performance through variations inplate geometrical profiles, and wherein the heat transfer plates withdifferent geometrical profiles may further be arranged within a sameplate pack in a hybrid fashion.
 36. The heat transfer plate dedicatedfor the multi-pass removable plate heat exchanger according to claim 34,wherein the heat transfer plate may obtain different thermal-hydraulicperformance through variations in plate geometrical profiles, andwherein the heat transfer plates with different geometrical profiles mayfurther be arranged within a same plate pack in a hybrid fashion. 37.The heat transfer plates specific for the multi-pass removable plateheat exchanger according to claim 35, wherein variations in geometricalprofiles may include, but are not limited to, varying chevroncorrugation angles, circular or irregular dimples, studs, or otherstructures for enhancing heat transfer efficiency.
 38. The heat transferplate specific for the multi-pass removable plate heat exchangeraccording to claim 33, wherein sealing and/or partitioningfunctionalities of the sealing gaskets may be partially or completelyreplaced by other sealing structures or mechanisms.
 39. The heattransfer plate specific for the multi-pass removable plate heatexchanger according to claim 34, wherein sealing and/or partitioningfunctionalities of the sealing gaskets may be partially or completelyreplaced by other sealing structures or mechanisms.
 40. The heattransfer plate specific for the multi-pass removable plate heatexchanger according to claim 38, wherein the other sealing structuresand mechanisms may include, but are not limited to, brazing, welding,diffusion bounding or mechanical contact sealing.